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U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 4 What is Wireless networking? A Wireless Local Area Network (WLAN) is a type of local- area network that uses high-frequency radio waves rather than wires to communicate between nodes. WLAN is a flexible data communication system used as an alternative to, or an extension of a wired LAN.

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U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 5 What are 802.11 WLANs? 802.11 is the part of the IEEE LMSC that defines wireless LAN networking First 802.11 wireless networks started showing up in the 90s Designed to connect in different way depending on environment –Stations can connect directly to one another (Ad-Hoc) –Stations can connect to Access Points (APs) to gain access to other networks 802.11 is the part of the IEEE LMSC that defines wireless LAN networking First 802.11 wireless networks started showing up in the 90s Designed to connect in different way depending on environment –Stations can connect directly to one another (Ad-Hoc) –Stations can connect to Access Points (APs) to gain access to other networks

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U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 46 Locating a Network Passive Scanning –Stations listen for a beacon frame –Based on the information contained, station may or may not attempt association Active Scanning –Station sends a probe request / listens for response –Attempt to associate based on information in response Passive Scanning –Stations listen for a beacon frame –Based on the information contained, station may or may not attempt association Active Scanning –Station sends a probe request / listens for response –Attempt to associate based on information in response

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U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 48 Infrastructure vs. Ad Hoc Infrastructure All traffic goes through AP Possible use of a Point Coordinator for polled access Requires Association Usually connects to a separate wired network Infrastructure All traffic goes through AP Possible use of a Point Coordinator for polled access Requires Association Usually connects to a separate wired network Ad Hoc All communication is direct Distributed nature of BSS functions No association Typically no network services found on a wired network available (DHCP, domain servers, etc.)

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U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 52 802.11n – High speed High Throughput Group –Looking to achieve speeds of >100Mbs Improve MAC efficiency –Using lots of the improvements for QoS, this would reduce the management overhead needed Higher data rates –Using MIMO and OFDM to get more data though –Use higher constellation sizes (256 QAM) –Higher bandwidth channels 40MHz instead of 20MHz –Takes advantage of multipath There are still multiple proposals about how to actually do this High Throughput Group –Looking to achieve speeds of >100Mbs Improve MAC efficiency –Using lots of the improvements for QoS, this would reduce the management overhead needed Higher data rates –Using MIMO and OFDM to get more data though –Use higher constellation sizes (256 QAM) –Higher bandwidth channels 40MHz instead of 20MHz –Takes advantage of multipath There are still multiple proposals about how to actually do this

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U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 53 802.11p – Vehicular Wireless Enable Wireless connections in vehicle-to-vehicle as well as vehicle-to-roadside locations –Would enable download of information about what is around you and what is going on –Could allow for more advanced services for cars EZPass type applications Accident prevention/preparation could occur Traffic and road condition report downloads More intelligent car navigation services Hard to do because vehicles are moving fairly quickly –Various nodes move in and out of range within seconds Range of ~1000 ft. 6Mbs in the 5.9GHz band Enable Wireless connections in vehicle-to-vehicle as well as vehicle-to-roadside locations –Would enable download of information about what is around you and what is going on –Could allow for more advanced services for cars EZPass type applications Accident prevention/preparation could occur Traffic and road condition report downloads More intelligent car navigation services Hard to do because vehicles are moving fairly quickly –Various nodes move in and out of range within seconds Range of ~1000 ft. 6Mbs in the 5.9GHz band

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U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 54 802.11s – Mesh Networking Mesh Networks are getting more and more popular –Many large cities are deploying large metropolitan mesh networks Philadelphia is one of the most notable –Allows for large networks to be built without the need for lots of cabled infrastructure. Takes a lot from Internet Protocol (IP) routing systems to allow for hopping through a network –routing needs to occur at the MAC layer and at the IP layer in order to deliver traffic to the clients or APs which are located across the network Many proprietary methods already exist –Tropos –Strix Mesh Networks are getting more and more popular –Many large cities are deploying large metropolitan mesh networks Philadelphia is one of the most notable –Allows for large networks to be built without the need for lots of cabled infrastructure. Takes a lot from Internet Protocol (IP) routing systems to allow for hopping through a network –routing needs to occur at the MAC layer and at the IP layer in order to deliver traffic to the clients or APs which are located across the network Many proprietary methods already exist –Tropos –Strix